Modern telecommunications system typically utilize digitally encoded data instead of analog data. If analog data is used, it is converted to digital data for the purposes of switching the data between conducting media. Switching of data occurs at large telecommunications switches, which may receive and process hundreds or thousands of data channels.
In the process of being switched, two or more individual data streams may be combined to form a single data stream. When two or more data streams are combined, the total amount of data being transmitted, or bandwidth, of the combined data stream equals the sum of the bandwidths of each of the individual data streams. Accurate control is required when combining the two or more individual data streams into a single data stream in order to prevent corruption of data on the data bus.
Although it is common to combine two or more data streams into a single data stream with equal bandwidth, it is not unusual for data transmission errors to be created when such combinations are created. Such errors prevent additional data processing from being performed on the two or more data streams while they are being combined, as the additional data processing would make such errors difficult or impossible to detect.